The effect of the season on some blood metabolites and haptoglobin in dairy cows during postpartum period

The aim of this study was to evaluate the effect of the season (ambient temperature and relative humidity) on some blood metabolites in dairy cows during postpartum period. Blood samples were collected from 195 clinically healthy dairy cows of 8 Italian dairy herds in spring (April-May 15.5±4 °C and 69.5±0.7 %), summer (June-July 23±1.5 °C and 69±1.3 %) and autumn (September-October 17±2 °C and 72.5±2 %). Total proteins, albumin, globulins, urea, glucose, triglycerides, total cholesterol, non-esterified fatty acids, β-hydroxybutyrate and haptoglobin were analysed. One-way repeated measures analysis of variance (ANOVA) showed a significant effect of the season (Pβ0.05) on all studied parameters, except to the packed cell volume, globulins and β-hydroxybutyrate. A positive significant correlation was found only between albumin and total cholesterol in summer (r=0.39; P<0.01) and autumn (r=0.40; P<0.001). These results indicated the influence of the season on blood metabolites in dairy cows during postpartum period.